A driver looks from an Uber self-driving car on September 13, 2016 in Pittsburgh, Pennsylvania.

Starting today, Uber's new in-app tipping option is being rolled out in 100 cities in the US and Canada, including major markets like New York City, San Francisco, and Los Angeles. After downloading an updated version of the app, riders will be asked whether they'd like to leave a tip when rating their driver at the end of a trip. Likewise, drivers will be prompted to choose whether they want to accept tips after updating their own apps.

The inclusion of in-app tipping is a major reversal for the embattled ride-hail company. For years, Uber has resisted including a tipping option in its app, even as major rivals like Lyft boasted of the millions of dollars in tips that was being distributed to its drivers. But after a series of major scandals, including revelations about pervasive sexual harassment and a toxic work environment, and the loss of some of its marketshare, executives at Uber finally changed course last month and decided to allow tipping.

(And in a Shakespearean twist, Uber CEO Travis Kalanick, the executive at the company most opposed to tipping, declared his own resignation a mere hours after the tipping option was first announced.)

I've long argued that Uber should do right by its drivers and include tipping. But there's no question this is going to piss off a significant segment of riders. A lot of people, millennials especially, liked Uber because it eliminated all the ambiguity in financial transactions. The idea of a cashless transaction was paramount to Uber's business model.

In an email to drivers, Uber says that tipping is part of its broader effort to improve conditions for them over the next 180 days: "Some changes will be big, some will be small — all will be the changes you've asked for."

In addition, Uber's new "pay for wait" program, in which customers will be charged a fee if the driver is still waiting two minutes after arriving at the pickup location, will be active in all US and Canadian markets starting today. Previously, Uber had been giving passengers a five-minute window.

Tipping will be live in all US and Canadian cities by the end of July. In the meantime, here's a list of the cities where it's now available: